I'm seeing lots of rumor sites stirring about a possible "Sub-$500" Mac. My first impression was, awesome, I can sell my 4 year old PowerMac and get a newer faster machine for cheap. My second impression, however, was a little less enthusiastic. If Apple releases a brand new computer for 500 bucks, how hard of a hit are our used ebay Macs gonna take? I know old Apples have a history of good resale value, but could this upset that trend? Anyone else have thoughts on what this could do to the used Mac seller community?